Firefox crashes at startup.

Firefox 19.0.2 crashes at startup. The crash report I get is the following:
Absturz-ID: bp-9f536c02-1fc0-476a-b443-d8ee52130323

I am using a desktop PC with Win7 Professional.

Backgroud information:

I did not get any issue with Firefox since Windows brought the KB2670838 patch a couple of weeks ago. With this patch, Firefox and IE couldn't start (crash at startup). Well, the solution was for me to uninstall this patch and to wait for a new Patch from Microsoft to solve that issue. The problem was indeed temporarily solved since a series of patches came around 10 days ago. Since then, IE works quite well, but Firefox has again an issue at startup: it crashes. I was able to start firefox in "secure or safe mode" so that I decided to wait a couple of days, with the hope that either a new win7 patch or a Firefox release would solve the issue.

10 days later (today), I decided to completely uninstall Firefox (according blog's instruction) including all remaining directories, and to install it again. Result: Firefox still crashes at startup, and cannot even start in "Safe mode".

Could you please advise what I should do ?
Remark: IE, Opera and Chrome work OK on my PC (nevertheless Firefox is my favorite browser, and I would like to use it further).

Thanks in advance for your help.

Firefox 19.0.2 crashes at startup. The crash report I get is the following:
Absturz-ID: bp-9f536c02-1fc0-476a-b443-d8ee52130323
I am using a desktop PC with Win7 Professional.
Backgroud information:
* I did not get any issue with Firefox since Windows brought the KB2670838 patch a couple of weeks ago. With this patch, Firefox and IE couldn't start (crash at startup). Well, the solution was for me to uninstall this patch and to wait for a new Patch from Microsoft to solve that issue. The problem was indeed temporarily solved since a series of patches came around 10 days ago. Since then, IE works quite well, but Firefox has again an issue at startup: it crashes. I was able to start firefox in "secure or safe mode" so that I decided to wait a couple of days, with the hope that either a new win7 patch or a Firefox release would solve the issue.
10 days later (today), I decided to completely uninstall Firefox (according blog's instruction) including all remaining directories, and to install it again. Result: Firefox still crashes at startup, and cannot even start in "Safe mode".
Could you please advise what I should do ?
Remark: IE, Opera and Chrome work OK on my PC (nevertheless Firefox is my favorite browser, and I would like to use it further).
Thanks in advance for your help.